Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B7/00—Closing containers or receptacles after filling
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
  • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
  • C09J7/22—Plastics; Metallised plastics
  • C09J7/24—Plastics; Metallised plastics based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
  • C09J7/241—Polyolefin, e.g.rubber
  • C09J7/243—Ethylene or propylene polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/03—3 layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2250/00—Layers arrangement
  • B32B2250/24—All layers being polymeric
  • B32B2250/242—All polymers belonging to those covered by group B32B27/32
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/514—Oriented
  • B32B2307/518—Oriented bi-axially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/54—Yield strength; Tensile strength
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
  • B32B2307/546—Flexural strength; Flexion stiffness
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2405/00—Adhesive articles, e.g. adhesive tapes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2519/00—Labels, badges
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment
  • C08J2323/10—Homopolymers or copolymers of propene
  • C08J2323/12—Polypropene
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J2301/00—Additional features of adhesives in the form of films or foils
  • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
  • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature

Definitions

• the present invention relates to the use of polyolefin-based films from rolls to obtain labels to be used in high speed labelling machines, the so called roll-fed application, higher than 8,000 up to about 75,000 containers/hour, preferably 15,000 to 60,000, the films having a thickness in the range from 10 to 22 ⁇ m, preferably from 14 to 20 ⁇ m, combined with a flexural rigidity (N.mm) in the range 0.5x10 -2 -4.5x10 -2 neglecting a constant 1/[12x(1- ⁇ 2 ) wherein ⁇ is the Poisson modulus related to the used polymer, ⁇ being of the order of 0.2-0.4 for polyolefins.
• the films of the present invention are preferably multilayer films with at least two layers, preferably three or more, generally 5 or 7 layers, etc., wherein the core layer is a propylene homopolymer with an amount of extractables in n-hexane (50°C for two hours) lower than 10% by weight, preferably lower than 5%, still more preferably lower than 2%, as determined according to the FDA 177 1520 standard, combined with a dimensional stability in machine direction (MD), determined according to the OPMA TC 4 standard (Oriented Polypropylene Manufacturer Association) at 130°C for 5 minutes in air ranging from 0 and -10%, preferably from -4 to -8.5%, and in transverse direction (TD) from -4 to +4%, preferably between 0 and +2.5%.
• MD machine direction
• OPMA TC 4 standard Oriented Polypropylene Manufacturer Association
• the films of the present invention are preferably obtainable by extrusion of polyolefin polymer granules up to obtain rools having very high lengths, even of the order of 20,000 meters. These are called extrusion mother rolls (neutral film). From these, by cutting, extrusion daughter rolls are obtained, preferably the diameter is up to 1,000 mm.
• the polyolefin-based films used in the present invention are preferably multilayers based on propylene homopolymer in the core and on propylene homopolymers and/or copolymers in the skin layers. The latter being equal to or different from each other.
• One of the skin layers, called in the present invention skin 1 is subjected to surface treatments for a good anchoring of inks to the film in the printing step.
• plastic films to obtain labels from rolls to be applied to containers in high speed manufacturing processes is known in the prior art.
• the printed plastic film adhesive-free roll is unwound and cut to size for obtaining labels. Then the machine applies the adhesive, for example of hot-melt type, on the label and applies it on the container.
• Patent application US 2002/0032295 relates to a propylene homopolymer film having improved barrier properties to steam and oxygen and improved mechanical properties.
• the film is biaxially oriented, has an isotactic index of at least 95% and does not contain hydrocarbon resins.
• the elastic modulus in longitudinal direction (MD) is higher than 2,500 N/mm 2 and in transversal direction (TD) is higher than 4,000 N/mm 2 .
• MD longitudinal direction
• TD transversal direction
• USP 5,118,566 discloses a biaxially oriented polypropylene film, used as adhesive tape, endowed with high mechanical resistance properties, the film comprising (% by weight) from 69 to 94.99% of a polyolefin, 5-35% of an hydrocarbon resin having softening point in the range 70°C-170°C and from 0.01% to 1% of a nucleating agent.
• the tape can be used to form labels.
• Patent application EP 79,520 discloses a polypropylene plastic film comprising a natural or synthetic resin with a softening point from 70 to 170°C in an amount from 1 to 30% by weight with respect to the total weight of the film, an elastic modulus in MD in the range 4,000 - 6,000 N/mm 2 , the film after extrusion and cooling is subjected to three stretching steps two of which are in MD.
• the film is used for packaging and as insulating material for condensers and as adhesive tape. No indication is given that these films can be used as labels.
• USP 4,595,738 discloses isotactic polypropylene films oriented by simultaneous biaxial stretching, wherein the stretching ratio is at least 1:45, with low residual tensile stress in MD, a specific puncture resistance and certain elongation factors.
• the film is particularly suitable to store optical or acoustic information, as adhesive tape for packaging or as layer for laminates. No indication is given that the disclosed films can be used as labels.
• USP 3,937,762 describes a polymeric composition and thermoplastic films obtained therefrom having improved physical properties, comprising a polyolefin containing a lower amount of a resin formed of a random multipolymer of a mixture comprising pentadiene 1,3 and at least one other monomer having one ethylenic unsaturation.
• the resin amount ranges from 5 to 40% by weight.
• USP 4,921,749 describes a film having an improved seal strength and improved barrier properties, comprising a core formed of 70%-97% by weight of a polyolefin and from 3 to 30% by weight of a low molecular weight resin different from polyolefins, for example an hydrogenated resin.
• a skin film is applied on at least one surface of the core, the ratio by weight between the skin film and the core ranges from 1% to 20%.
• the skin layer comprises a random copolymer formed of 80% to 99% by weight of propylene and from 1 to 20% of ethylene.
• the resin has a molecular weight lower than 5,000 and a softening point from 60°C to 180°C.
• Patent application US 2003/0148,119 relates to a heat-sealable coextruded oriented polyolefin multilayer film having at least one propylene polymer with high crystallinity and with an isotactic index higher than 95% by weight mixed with an hydrocarbon resin up to 10% by weight.
• the film can be subjected to corona, flame, plasma treatment on one surface. On the other surface there is a heat-sealing layer.
• the film shows a very good resistance to distortion caused by food oils and, having good barrier properties to said oils, is used in the snack food packaging industry. In this patent application no indication is given that the film can be used for labels.
• Patent application CA 2,047,469 describes a heat-sealable film comprising a base polypropylene layer and an hydrocarbon resin having a softening point of at least 140°C, and at least one top layer comprising (a) an ethylene/propylene copolymer having an ethylene content not higher than about 10% by weight, (b) a propylene/1-butene copolymer, (c) a propylene/ethylene/alpha-olefin terpolymer or a blend of two or more of the above polymers. At least one of these layers contains an anti-blocking agent or a lubricant.
• the film shows better barrier properties to steam and oxygen, good slip properties and low shrinkage values. In this patent application no indication is given that the film can be used for labels.
• the polypropylene labels in commerce for this application are wound in rolls having a film thickness from 30 to 40 ⁇ m.
• the Applicant has unexpectedly and surprisingly found that the above technical problem on the use of a lower amount of plastics for reducing the energy consumption necessary for their manufacture and reducing the amount of CO 2 and thus to reach a lower green house effect (GWP) and a lower amount of labels to be recycled/disposed of at the end of their life cycle, has been solved according to the present invention by the use of a film, as defined below, based on polyolefins from rolls for preparing labels to be used in high speed labelling machines (roll-fed applications) higher than 8,000 up to about 75,000 containers/hour, with a number of scraps during label application to containers lower than 2%, preferably lower than 1%, more preferably lower than 0.3%, even more preferably lower than 0.1%, combined with a number of scraps during the transformation step lower than 5% preferably lower than 3%, net of trimmed edges.
• a film as defined below, based on polyolefins from rolls for preparing labels to be used in high speed labelling machines (roll-fed applications) higher than
• containers are bottles, cans, etc.
• the films have elastic modulus (N/mm 2 ) in TD lower than 3,500 and in MD (N/mm 2 ) from 2,600 to 3,800 preferably from 3,000 to 3,600.
• the speed of the roll-fed application ranges from 15,000 to 60,000 containers/hour.
• the film thickness is in the range from 14 to 20 ⁇ m.
• the flexural rigidity (N.mm) is in the range from 0.7x10 -2 to 3.5x10 -2 , more preferably from 0.8x10 -2 to 3.0x10 -2 , still more preferably from 0.9x10 -2 to 2.8x10 -2 .
• the elongation at break in MD is lower than 120%, more preferably lower than 110%.
• the elongation at break in MD ⁇ 80%, more preferably ⁇ 90%.
• the elastic modulus in TD is ⁇ 2,500, more preferably ⁇ 2,700 N/mm 2 .
• the tensile strength at break ranges from 228 to 170 N/mm 2 .
• the dimensional stability of the film of the invention in MD is in the range from -4 to -8.5% and in TD from 0 to +2.5%.
• the polyolefin-based plastic films are preferably based on propylene homopolymers having an extractable amount in n-hexane (50°C for two hours) lower than 10% by weight, as determined according to the FDA 177 1520 standard and preferably a melt flow index (MFI)in the range from 1.0-10 g/10 min (230°C 10 min - load 2.16 Kg ASTM D1238).
• MFI melt flow index
• the label is obtained after printing and cutting the roll and on the roll-fed line the machine applies the adhesive, for example of hot melt type, according to vertical sectors on the initial and end part of the label for its correct application on the container.
• the adhesive for example of hot melt type
• the propylene homopolymers have an amount of extractables, determined with the above method, lower than 5%, more preferably lower than 2%.
• the films of the present invention are preferably in multilayer films, comprising:
• the olefinic copolymers of the skin layers are selected from copolymers of propylene with at least another at least one ethylenic unsaturation containing comonomer, preferably selected from ethylene and alpha-olefins having a number of carbon atoms ranging from 4 to 12, the total comonomer amount ranging from 0.5 to 25% by weight, preferably from 1 to 7% by weight on the total polymer monomers.
• the comonomers containing at least one ethylenic unsaturation are for example ethylene, butene, hexene, octene, decene, dodecene.
• the comonomer is ethylene.
• the copolymers contain (% by moles) ethylene from 0 to 33%, preferably 3-15%, more preferably 5-10%.
• the alpha-olefinic monomer (% by moles) is comprised in the range 0-10%, preferably 0.5-6%.
• comonomers that can be present in the copolymers are cyclopentadiene and terpenes, in an amount by moles up to 10%, preferably 0-5%.
• the propylene copolymers have an amount of extractables lower than 10% by weight, preferably lower than 3%.
• the melt flow index of the propylene copolymers preferably ranges from 1 to 30 g/10 min (230°C 10 min load 2.16 Kg ASTM D1238).
• the articles to be labelled are bottles having a volume comprised between 0.25 and 2.5 liter, preferably from 0.5 to 1.5 liter
• polyolefin-based plastic films preferably propylene polymers
• polyolefin-based plastic films preferably propylene polymers
• the polyolefin-based plastic films preferably propylene polymers, have:
• the film is preferably multilayer and comprises a core: propylene homopolymers as defined above, skin layers, equal to or different from each others: propylene homopolymers or propylene copolymers having the above characteristics.
• the Applicant has unexpectedly and surprisingly found that it is possible to obtain labels from roll for high speed roll-fed applications as indicated above by using films having a very low thickness with respect to the commercial standard films at present used even though the labels of the present invention have a rigidity remarkably lower than the commercial ones.
• the bottles have preferably a cylindrical or square or oval shape; the surface where the label is applied is preferably smooth.
• the combination of properties of the films of the invention allows to use them also in labelling machines wherein the film is subjected to tensions during the application.
• the film can be used also in labelling machines wherein the film is not subjected to strong tensions.
• the film of the present invention can be subjected to adhesive sector spreading to obtain preadhesivized labels to be applied directly in the machine without using a hot glue applicator.
• the adhesive is preferably pressure sensitive.
• the film, preferably multilayer, of the invention is oriented at least in one direction, preferably it is bioriented.
• the skin layer can comprise optional components selected from slip agents, anti-blocking agents; the core can comprise optional components selected from antistatic agents, dyestuffs, hydrocarbon resins, olefinic copolymers, etc.
• the core can comprise optional components selected from antistatic agents, dyestuffs, hydrocarbon resins, olefinic copolymers, etc.
• no dyestuff is used, while for films printed in the outer (skin) layer with a high covering power (higher optical density and lower film transmittance) dyestuffs are used, in particular masterbatches based on TiO 2 .
• slip agents the following ones can be mentioned: higher aliphatic acid amides, higher aliphatic acid esters, waxes, salts of fatty acids with metals and polydimethyl siloxanes.
• the amount is the one generally used in films.
• inorganic compounds as silicon dioxide, calcium carbonate and the like can be mentioned.
• the amount is generally comprised between about 0.1 and about 0.5% by weight with respect to the layer weight.
• antistatic agents aliphatic tertiary amines with saturated linear chains containing an aliphatic C 10 -C 20 chain and substituted with ⁇ -hydroxy-(C 1 -C 4 ) alkyl groups, can be mentioned.
• tertiary amines N,N-bis(2-hydroxyethyl) alkylamines containing C 10 -C 20 , preferably C 12 -C 18 alkyl groups, can be mentioned.
• the amount of antistatic agent is generally comprised between about 0.05% and about 0.2% with respect to the layer weight.
• hydrogenated hydrocarbon resins having preferably a softening point determined according to ASTM E28 ranging from 130°C to about 180°C, can be added in amounts ranging from about 2% to 40% by weight, preferably lower than 20%, still more preferably from 4 to 12%, the percentages being based on the total weight of the olefinic polymer plus the hydrocarbon resin.
• the hydrocarbon resin is a low molecular weight synthetic resin having a softening point between about 130°C and 160°C; the number average molecular weight preferably ranges from 200 to 1,000.
• Hydrocarbon resins of this type preferably comprise one or more of the following monomers: styrene, methylstyrene, vinyltoluene, indene, pentadiene, cyclopentadiene and the like. Hydrogenated resins of cyclopentadiene are preferred.
• the hydrocarbon resin if desired, can be added also in the skin layers.
• propylene-based olefinic copolymers as indicated above can be added, or copolymers of ethylene with one or more linear or branched alpha olefins from 3 to 20 carbon atoms, optionally in the presence of other comonomers, containing more than one double bond in addition to the alpha-olefinic double bond, conjugated or not, from 4 to 20 carbon atoms, or cyclic olefins wherein the ring has 5 or 6 carbon atoms, preferably cycloalkenes, such as vinylcyclohexene; aromatic olefins such as cyclopentadiene; vinylaromatic such as styrene.
• the alpha-olefinic and dienic monomers can be selected from those indicated above, propylene included.
• the total amount of comonomers ranges from 5 to 50%, preferably from 10 to 25%, the number average molecular weight being preferably in the range 300-25,000.
• the amount of olefinic copolymers (% by weight), added in the film or in the core ranges from 0 to 20% with respect to the amount of propylene homopolymers of the film or of the core, preferably from 0 to 10%, still more preferably 0-3%.
• intermediate layers can be used, made of copolymers and/or hydrocarbon resins, provided that the outer layers of the film of the present invention remain as above defined.
• the layer to be printed is preferably treated with known methods to modify the surface tension, to improve the anchorage of the printing inks and/or adhesives. Preferably corona, flame or plasma treatment is used.
• the films of the invention can be obtained by known technologies for manufacturing films, preferably polyolefin-based multilayer films, in particular based on propylene homopolymers or propylene-based copolymers.
• a particularly preferred process is the simultaneous stretching technology Lisim®. This technology is described in several patents, as for example USP 4,853,602 , USP 5,051,225 .
• the process for the manufacture of the multilayer films comprises the following steps:
• the MD stretching ratio can be considered equal to the ratio between the film speed at the outlet of the stretching frame and the film speed at the inlet of the film into the stretching frame.
• this ratio is equivalent to the ratio between the frequency of the alternate current fed to the linear electric mot ors at the outlet of the stretching frame and the frequency of the alternate current fed to the linear motors at the inlet of the stretching frame.
• the stretching ratio in TD can be considered with a good approximation equivalent to the ratio between the film width at the outlet of the stretching frame and the film width at the inlet of the stretching frame.
• Lisim® it is possible to obtain a positive dimensional stability value (dilatation).
• a negative value of dimensional stability is obtained.
• modifications in the printing step have to be introduced to take into account the film shrinkage in TD. Therefore the Lisim® simultaneous stretching technology allows to remarkably simplify the printing step, as no intervention is requested on the printing machine.
• the films of the present invention are endowed of excellent mechanical properties as shown by their tensile properties (tensile strength at break, elastic modulus, elongation at break) determined according to ASTM D 882.
• the films of the invention have also good optical properties as shown by the gloss and haze values.
• the films of the present invention after surface treatment are printed by conventional techniques and used for roll-fed labelling.
• a further object of the present invention are polyolefin-based plastic films as defined above.
• the plastic films of the present invention have an elastic modulus in TD lower than 3,500 N/mm 2 , in MD in the range from 2,600 to 3,800 N/mm 2 , preferably from 3,000 to 3,600 N/mm 2 .
• the films of the present invention are generally obtainable by extrusion of granules of polyolefinic polymers and the obtained films, preferably after having been oriented and heat set, are wound in rolls called extrusion mother rolls (neutral, i.e. untreated film). By cutting, extrusion daughter rolls are obtained therefrom.
• extrusion mother rolls neutral, i.e. untreated film
• transformation mother rolls transformation mother rolls
• transformation mother rolls transformation mother rolls and are subjected to printing and cutting processes to get the rolls of printed film for the end use.
• a further object of the present invention are labels obtainable from the above plastic films.
• the films of the present invention allow to obtain advantages from an industrial point of view, as with rolls for roll-fed application having the same diameter of rolls of the commercial films, which generally show a thickness from 30 to 40 ⁇ m, it is possible to obtain a lower impact on the production, transportation and storage costs, as the roll film length is greater.
• the roll diameter being the same as that of commercial films, brings to fewer roll substitutions and therefore fewer machine downtimes, giving a higher yield on the labelling lines with a number of scraps lower than 2%, preferably lower than 1%, more preferably lower than 0.3%, even more preferably lower than 0.1%, combined with a number of scraps in the transformation step lower than 5% preferably lower than 3%, net of trimmed edges.
• the melt flow index was determined at 230°C for 10 min with a load of 2.16 Kg according to ISO 1133.
• the extractables are determined by extracting a sample of the polymer with n-hexane at 50°C for two hours according to FDA 177 1520 Standard.
• the film dimensional stability is determined according to OPMA TC 4 standard by heating a sample having 20 cm x 1 cm sizes at 130°C for 5 minutes in the air.
• the number of the dimensional stability is preceded by -, if the sample dilates, by +.
• the modulus of Young, or elastic modulus (N/mm 2 ) has been determined according to the ASTM D 882 standard both in MD direction and in TD direction.
• the elongation at break and tensile strength at break (N/mm 2 ) of the film are determined by ASTM D 882.
• the Haze values are determined according to ASTM D 1003.
• the Gloss values are determined according to ASTM D 2457 standard.
• scraps are calculated with reference to the weight of the starting film roll.
• scraps are calculated with reference to the number of containers discarded with respect to those obtained.
• the film has been obtained by coextruding through a flat head three polymeric layers, respectively, the core and the skin layers.
• the core has been extruded at extruder temperatures in the range 235°C-255°C, the skin layers at extruder temperatures comprised between 260°C-275°C.
• the three layers have been coextruded in a flat head at the temperature of 245°C.
• the so obtained sheet has been cooled to a temperature of 25°C on a chill roll, partly dipped in a water bath having a temperature of 28°C.
• the chilled sheet passed through an infrared heating battery wherein the surface temperature of the heating panels was comprised between 200°C and 320°C. Then the sheet entered a simultaneous stretching oven Lisim® wherein:
• the flexural rigidity of the film was 2.20x10 -2 N.mm.
• the Young modulus of the film in TD direction was 2780 N/mm 2 .
• Example 1 was repeated but using in the core 90% by weight of propylene homopolymer of Example 1 + 10% by weight of masterbatch of amorphous hydrocarbon resins with polypropylene carrier Constab MA00929PP (see for example the technical card KafritGroup of July 2010).
• the thickness of the core and of the skin layers was as in the film of example 1.
• the flexural rigidity of the film was 2.61x10- 2 N.mm.
• the Young modulus of the film in TD direction was 3152 N/mm 2 .
• Example 2 was repeated but using in the core 89% by weight of propylene homopolymer of example 1, + 1% by weight of antistatic agent ASPA2446 (Schulmann®) masterbatch with propylene homopolymer carrier, instead of 90% by weight of propylene homopolymer.
• ASPA2446 Schotter®
• the flexural rigidity of the film was 2.47x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3374 N/mm 2 .
• Skin 2 was 94% by weight of propylene homopolymer + 6% by weight of masterbatch comprising the slip agent in polypropylene carrier as used in skin 2 of example 1.
• the core thickness was of 17 ⁇ m, the thickness of each skin layer was 1 ⁇ m.
• the flexural rigidity of the film was 2.17x10 -2 N.mm.
• the Young modulus of the film in TD direction was 2904 N/mm 2 .
• Example 4 was repeated but with skin 2 having the same composition as skin 2 of the film of example 3.
• the thickness of each of the three layers was as in the film of example 4.
• the flexural rigidity of the film was 2.24x10 -2 N.mm.
• the Young modulus of the film in TD direction was 2928 N/mm 2 .
• Example 1 was repeated but the core was the same as in example 3 i.e., 94% by weight of PP homopolymer, + 5% by weight of the masterbatch of amorphous hydrocarbon resins with polypropylene carrier Constab® MA00929PP, + 1% anatistatic masterbatch.
• the thickness of each of the three layers was as in the film of example 4.
• the flexural rigidity of the film was 2.24x10 -2 N.mm.
• the Young modulus of the film in TD direction was 2878 N/mm 2 .
• Example 6 was repeated but in the core 94% polypropylene was formed of 84% by weight of propylene homopolymer used in example 6 + 10% of reclaim (regranulated) propylene polymers.
• the thickness of each of the three layers was as in the film of example 4.
• the flexural rigidity of the film was 2.24x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3100 N/mm 2 .
• Example 7 The film of Example 7 was wound in a roll (extrusion mother roll) that was cut to obtain extrusion daughter rolls having width 630 mm and film length 22,000 m, external diameter 780 mm, density 0.91 g/cm 3 , for the 2 colour reverse rotogravure printing for preparing labels to be applied on 0.5 liter PET bottles.
• the roll film has been printed at a line speed of 280 meters/min for 80 minutes.
• the print scraps amounted to 400 meter corresponding to a weight of 4.5 kg.
• extrusion daughter rolls were cut to obtain transformation daughter rolls, each having width 68 mm width, roll diameter 600 mm and film length 10,000 m. 18 rolls were overall obtained in two working cycles. Cutting was carried out at a line speed of about 600 m/min without the formation of creases and folds. The total amount of scraps in the transformation step (cutting + printing), net of trimmed edges, was lower than 3%.
• the roll fed application lasted 2 hours.
• the line speed was up to 60,000 bottles/h (bph) (average speed line about 55,000 bph), and the label cut from the roll was found to be precise and clear, the print pitch regular and constant.
• the discarded bottles were 92 on about 115,000 (0.08%).
• This example shows that the rolls of the films of the present invention can be used in roll-fed application to manufacture labels without jamming at a speed line also of 60,0000 bph).
• the roll fed application lasted 2 hours.
• the line speed was up to 44,000 bph (average speed line 42,000 bph) and the label cut resulted precise and clearcut, the print pitch regular and constant.
• the discarded bottles were 43 over about 85,000 (0.05%).
• the printed transformation daughter rolls obtained in example 7A having length 10,000 m, roll diameter 600 mm but width 85 mm, were used to obtain labels having length 320 mm and width 59 mm for application on a roll-fed labelling machine to 2.0 liter cylindrical PET bottles.
• the roll fed application lasted 2 hours.
• the line speed was up to 36,000 bph (average speed 34,000 bph) and the label cut resulted precise and clearcut, the print pitch regular and constant.
• the discarded bottles were 18 over about 70,000 (0,024%).
• Example 7 was repeated but substituting in the core 94% of PP homopolymer with 69% of PP homopolymer + 25% of masterbatch of titanium dioxide (white 70) with polypropylene carrier.
• the masterbatches of amorphous resin and of antistatic were in the same amounts as in ex. 7.
• the thickness of each of the three layers was as in the film of example 4.
• the flexural rigidity of the film was 2.26x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3192 N/mm 2 .
• the flexural rigidity of the film was 1.22x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3107 N/mm 2 .
• Example 9 was repeated but the core thickness was 11 ⁇ m and the thickness of each skin layer was 2 ⁇ m.
• composition of skin 2 was 93% by weight of polypropylene homopolymer ADSTIFHA612M (LyonellBasell®) having MFI 6, + 6% by weight of slip agent ABVT34SC (Schulmann®) masterbatch based on silicone particles having a 2 ⁇ m diameter, + 1% by weight of a silica masterbatch in polypropylene AB 6001PP.
• the flexural rigidity of the film was 1.25x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3163 N/mm 2 .
• Example 9 was repeated but the layer composition was the following:
• the thickness of the layers was as in example 9.
• the flexural rigidity of the film was 1.0x10 -2 N.mm.
• the Young modulus of the film in TD direction was 3050 N/mm 2 .
• Example 7A was repeated but using a commercial film Stilan® TP 35 having thickness 35 ⁇ m.
• the film length of the extrusion daughter rolls was of 13,500 m, that is about one half that of the corresponding rolls of example 7A (22,000 m). During the processing step it was compulsory to slow down line speed to change the rolls and make the relevant joints.
• Thickness ⁇ m Core Skin 1 (subjected to surface treatments) Skin 2 Ultimate tensile stress Elongation in MD % Elastic modulus in MD N/mm 2 Dimensionalstability in % MD TD 1 19 PP Homopolymer 99% PP homopolymer +1% silicamasterbatch 93% PP homopolymer +1% silica masterbatch +6% slip agentmasterbatch 226 102 3200 - 7.3 + 1.4 2 19 90% PP homopolymer + 10% masterbatch of amorphous resins 99% PP homopolymer+1% silicamasterbatch 93% PP homopolymer +1% silica masterbatch + 6% slip agent masterbatch 209 97 3800 - 9 +0.9 3 19 89% PP homopolymer + 10% masterbatch of amorphious resins + 1% antistatic masterbatch 99% PP homopolymer +1% silicamasterbatch 93% PP homopolymer +1% silica masterbatch + 6% slip agent master

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Laminated Bodies (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Organic Insulating Materials (AREA)
• Materials For Medical Uses (AREA)
• Shaping By String And By Release Of Stress In Plastics And The Like (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=45571655

Family Applications (1)

Country Status (4)

Cited By (3)

Citations (14)

Family Cites Families (1)

• 2011
  • 2011-12-02 IT IT002205A patent/ITMI20112205A1/it unknown
• 2012
  • 2012-11-29 US US13/689,570 patent/US20170253011A9/en not_active Abandoned
  • 2012-11-30 ES ES12194941.6T patent/ES2663631T3/es active Active
  • 2012-11-30 EP EP12194941.6A patent/EP2599628B1/fr not_active Not-in-force

Patent Citations (15)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events